ES2377527T3 - Fire retardants suitable for use in viscoelastic polyurethane foams - Google Patents

Abstract

The present invention relates to viscoelastic polyurethane foam formulations, viscoelastic polyurethane foams formed from such formulations, and products formed from the viscoelastic polyurethane foams.

Description

Fire retardants suitable for use in viscoelastic polyurethane foams

FIELD OF THE INVENTION

The present invention relates to viscoelastic polyurethane foam formulations, viscoelastic polyurethane foams formed from such formulations and to products formed from viscoelastic polyurethane foams.

BACKGROUND OF THE INVENTION

Flexible viscoelastic polyurethane foam (also known as "dead" foam, "slow recovery" foam or "high damping" foam) is characterized by a gradual gradual recovery of compression. Although most of the physical properties of viscoelastic foams resemble those of conventional foams, the resilience of viscoelastic foams is much lower, generally less than 15%. Appropriate applications for viscoelastic foam benefit from its conformation, energy attenuation and sound damping characteristics. For example, foam can be used in mattresses to reduce pressure points, in padding or sports helmets as a shock absorber and in car interiors for soundproofing. US-B1-6 316 514 discloses flexible viscoelastic polyurethane foams sound dampers and energy absorbers. Example 5 discloses a composition comprising chlorinated phosphate ester flame retardants (see column 8 1.46-49), mixtures of isocyanates and a diol that is protected with 100% primary hydroxyl groups.

Due to the uses of products produced from viscoelastic flexible polyurethane foams, it is desirable that these products have fire retardant qualities.

SUMMARY OF THE INVENTION

In one embodiment, the present invention relates to a flexible viscoelastic polyurethane foam formulation comprising a) a fire retardant amount of i) one or more chlorinated phosphate esters, ii) one or more brominated flame retardants, iii) one or more flame retardants phosphorus-based halogen-free, or iv) combinations of i), ii) and / or iii), b) at least one isocyanate having a functionality of at least two; c) at least one diol in which in the range of 50% to 95% of the terminal OH groups of the diol are primary OH groups; and, optionally, d) one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine; vi) plasticizers, vii) catalysts, viii) water, ix) alternative blowing agents such as methylene chloride, x) pigments, xi) cell openers.

In another embodiment, the present invention relates to a method of forming a flexible viscoelastic polyurethane foam comprising contacting in the presence of one or more catalysts: a) a flame retardant amount of i) one or more chlorinated phosphate esters, ii ) one or more brominated flame retardants, iii) one or more phosphorus-based halogen free flame retardants or iv) combinations of i), ii) and / or iii), b) at least one isocyanate having a functionality of at least two; c) at least one diol in which in the range of 50% to 95% of the terminal OH groups of the diol are primary OH groups; and, optionally, d) one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine; vi) plasticizers, vii) water, viii) alternative blowing agents such as methylene chloride, ix) pigments, x) cell openers.

In another embodiment, the present invention relates to a flexible viscoelastic polyurethane foam formulation derived or derivable from: a) a flame retardant amount of i) one or more chlorinated phosphate esters, ii) one or more brominated flame retardants, iii) one or more phosphorus-based halogen-free flame retardants or iv) combinations of i), ii) and / or iii), b) at least one isocyanate having a functionality of at least two; c) at least one diol in which in the range of 50% to 95% of the terminal OH groups of the diol are primary OH groups; and, optionally, d) one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine; vi) plasticizers, vii) catalysts, viii) water, ix) alternative blowing agents such as methylene chloride, x) pigments, xi) cell openers.

In other embodiments, the present invention relates to articles made of the flexible viscoelastic polyurethane foam formulations of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the common technology used to manufacture viscoelastic polyurethane foams relies on defects in the structure of the polyurethane net, that is, "hanging chains." Currently, the creation of defects in the foam is obtained through the use of formulations designed to have an insufficiency of isocyanate groups. By doing so, the foam producers ensure that, after the reaction between the isocyanate and the polyol, some hydroxy groups supported by the polyol molecules remain unreacted in the foam thus formed. Unreacted hydroxy groups are the "pendant chains" that create the desired "slow recovery" characteristics of viscoelastic polyurethane foams. More recent technologies have been developed for viscoelastic foams that are based on the use of polyol combinations that contain a large proportion of monofunctional materials (i.e., monoles). After the completion of the reaction, these monoles act as hanging materials and impart the desired viscoelastic properties to the foam. Such polyol combinations containing monoles allow the use of a higher concentration of isocyanate, which sometimes approximates the isocyanate index of 100. However, the present inventors have discovered that by using specific diols, such as those described herein. , and the flame retardants described herein, a flexible viscoelastic polyurethane foam or foam formulation can be produced without creating pendant chains, that is, without using a formulation designed to ensure an insufficiency of isocyanate groups, sometimes referred to as an isocyanate index of 100. This is a particularly desired quality of the foams of the present invention because, during combustion, these hanging chains induce intense dripping that makes it extremely difficult, in some cases bordering on the impossible, even with large loads of flame retardants and agents synergistic, meet fire standards such as BS5852 c rib 5 in which the weight loss that occurs during combustion is a test criterion. In addition, adding large loads of solid flame retardant synergic material such as melamine eliminates the desired slow recovery behavior of the foam without leading to a significant improvement in fire retardance, nor achieving consistent positive results in standard tests for fire such as BS5852 crib 5.

Isocyanates suitable for use in the present invention include any isocyanate used in the production of flexible polyurethane foams. These isocyanates, most preferably diisocyanates, are well known components of polyurethane foams and polyurethane foam formulations and include any compounds possessing at least one reactive group with free cyanate, and most preferably two, although they can be used more. Such compounds may also be aliphatic or aromatic in nature. Non-limiting examples of isocyanates suitable for use in the present invention include aromatic, aliphatic and cycloaliphatic polyisocyanates and combinations thereof such as phenylene m-diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, cyclohexane 1,4-diisocyanate, hexachotrotoluene diisocyanate (and isomers), naphthalene 1,5-diisocyanate, 2,4- 1-methoxyphenyl diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-biphenylene diisocyanate, 4,4'-3,3'-dimethoxy-biphenyl diisocyanate, 4,4'-3,3'-diisocyanate -dimethyl-biphenyl and 3,3'-dimethyldiphenylmethane 4,4'-diisocyanate; triisocyanates such as 4,4 ', 4 "-triphenylmethanetrisocyanate and toluene 2,4,6-triisocyanate; and tetraisocyanates such as 2,4'-5,5'-tetraisocyanate of 4,4'-dimethyldiphenylmethane and Polymeric polyisocyanates such as polymethylene polyphenylene polyisocyanate Raw polyisocyanates can also be used in the compositions of the present invention, such as crude toluene diisocyanate obtained by phosgenation of a mixture of toluenediamines, or crude diphenylmethane methane diamine methane diamine These raw isocyanates are disclosed in U.S. Pat. No.

3,215,652.

The most predominantly used isocyanates, and thus the most preferred types for this invention (although not required), are toluene diisocyanate ("TDI"), diphenylmethane diisocyanate ("MDI") or methylene diisocyanate (others may be used, such as aliphatic isocyanates, as well as other aromatic types). The polyol is generally reacted with a slight excess of isocyanate (ratio of hydroxyl OH groups in the NCO isocyanate groups of 1: 0.85 to 1: 1.40) to produce a soft flexible foam product; The higher the ratio, the harder the foam will be produced.)

The diols suitable for use in the present invention may be either polyether or polyester diols. The diols used in the practice of the present invention are those in which in the range of 50% to 95% of the OH groups of the diol are primary OH groups. In preferred embodiments, the diols are those in which in the range of 65% to 90%, more preferably in the range of 70% to 85%, of the diol OH groups are primary OH groups.

Diols suitable for use herein can also be described as having a number average molecular weight of more than 1000 g / mol, preferably in the range of 1000 g / mol to 4000 g / mol, more preferably in the range of 1500 g / mol to 3000 g / mol.

Preferred diols are polyoxyalkylene diols. In some embodiments, the polyoxyalkylene diols may have any desired arrangement of polyoxyalkylene units. For example, the polyoxyalkylene diols can be homopolymers based on propylene oxide, block copolymers of ethylene oxide ("EO") -PO, random EO / PO copolymers, PO-based polyols that are "protected" or "terminated" with a mixture of EO and PO to achieve a desired primary hydroxyl content, or any other desired configuration. In a particularly preferred embodiment, the polyalkylene diol used in the practice of the present invention is a PO-based polyol terminated with EO to achieve the desired primary hydroxyl content. In some embodiments, the polyalkylenediols used in the practice of the present invention are those that have a percentage of EO added as a "termination" over total PO + EOs added during manufacturing in the range of 1% to 20%, preferably 5 % to 15%, more preferably from 9% to 13%.

The viscoelastic formulations of the present invention also contain a flame retardant, in some embodiments a flame retardant amount of a flame retardant, selected from i) one or more chlorinated phosphate esters, ii) one or more brominated flame retardants, iii) one or more flame retardants free from phosphorus-based halogen or iv) combinations of i), ii) and / or iii). A flame retardant quantity is understood as that quantity sufficient to meet or exceed the test standards indicated in the BS5852 flammability test. Generally, depending on the density of the foam, this is in the range of 5 to 50 parts per one hundred parts of polyol or polyols ("php") of the flame retardant additive. In preferred embodiments, a flame retardant amount should be considered in the range of 10 to 35 php, more preferably in the range of 12 to 25 php.

Chlorinated phosphate esters suitable for use herein can be selected from any chlorinated phosphate esters, which are conventionally used in the art of making flexible flame retarded polyurethane foams.

Specific examples of suitable chlorinated phosphate esters used in exemplary embodiments are: tris (1,3-dichloropropyl) phosphate; also known as TDCP, tris (2-chloropropyl) phosphate, also known as TCPP or TMCP, 2,2-bis (chloromethyl) -1,3-propylene bis [di (2-chloroethyl) phosphate], also known as V6, tris phosphate (2-chloroethyl), also known as TCEP.

In these embodiments, the chlorinated phosphate esters used in the present invention typically contain in the range of 5 to 15% by weight of organic phosphorus, based on the total weight of the phosphate ester. Preferably, the organic phosphorus content is in the range of 6 to 13% by weight, on the same basis, and in more preferred embodiments the organic phosphorus content is in the range of 7 to 12% by weight, on the same basis. .

In these embodiments, the chlorinated phosphate esters used in the present invention typically contain in the range of 20 to 60% by weight of chlorine, based on the weight of the phosphate ester. Preferably, the chlorinated phosphate esters contain in the range of 30 to 50% by weight, of chlorine, on the same basis.

Bromine-containing flame retardants suitable for use in the invention can be either reactive or non-reactive, that is, they react or not with the isocyanate and can be selected from any of those used in the technique of making flame retarded polyurethane foams.

Specific examples of brominated flame retardants used in exemplary embodiments are tetrabromophthalic anhydride diester / ether containing reactive bromine. A commercial example of this class of products is Saytex® RB-79.

In these embodiments, brominated flame retardants for use in the present invention typically contain in the range of 10 to 70% by weight of bromine, based on the total weight of the brominated flame retardant. Preferably, the bromine content is in the range of 25 to 60% by weight, on the same basis. In more preferred embodiments, the bromine content of the brominated flame retardant is in the range of 35 to 55% by weight, based on the total weight of the brominated flame retardant.

The phosphorus-based halogen-free flame retardants for use in the invention can be reactive or non-reactive, that is, they react or not with the isocyanate, and can be selected from any of those used in the technique of making flame retarded polyurethane foams . Typical classes of phosphorus-based halogen-free flame retardants suitable for use in the invention are phosphates, phosphonates, phosphites, phosphinates as well as aminoalkyl compounds thereof.

In these embodiments, phosphorus-based halogen-free flame retardants typically contain in the range of 5 to 40% by weight of phosphorus, based on the total weight of the phosphorus-based halogen-free flame retardant. Preferably, the phosphorus content is in the range of 10 to 30% by weight, on the same basis.

The viscoelastic foam formulations of the present invention may include, and in some embodiments include, one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine; vi) plasticizers, vii) catalysts, viii) water, ix) alternative blowing agents such as methylene chloride, x) pigments, xi) cell openers. In some embodiments, one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine: vi) plasticizers, vii) catalysts, viii) water, ix) agents Alternative expansion such as methylene chloride, x) pigments, or xi) cell openers. These optional components are well known in the art and the amount of these optional components is conventional and not critical to the present invention.

Usable chain extenders and / or crosslinkers are diols and / or triols with molecular weights less than 250 and particularly between 50 and 200. Usable diols are aliphatic, cycloaliphatic or aromatic types, e.g. eg, ethylene glycol, diethylene glycol, dipropylene glycol and 1,4 butanediol. Usable triols include, for example, trimethylolpropane and glycerin.

Examples of suitable surfactants are emulsifiers such as sodium salts of sulfates or fatty acids of

5 castor oil; fatty acid salts with amines, e.g. eg, diethylamine oleate and diethanolamine stearate; sulphonic acid salts, e.g. eg, alkali metal or ammonium salts of dodecylbenzenedisulfonic acid and ricinoleic acid; foam stabilizers such as siloxane-oxyalkylene copolymers and other organopolysiloxanes, ethoxylated alkylphenols, ethoxylated fatty alcohols and castor oil. Other suitable surfactants are organosilicone surfactants.

Suitable plasticizers include dioctyl phthalate, distearyl phthalate, diisodecyl phthalate, dioctyl adipate, tricresyl phosphate, triphenyl phosphate and the like.

The viscoelastic foams of the present invention can be prepared by combining viscoelastic foam formulations, a) -c), using an isocyanate index greater than 95%, together with any optional components i) -xi), with one or more catalysts and one or more expanding agents, or individual components can

15 be combined in the presence of one or more catalysts and one or more expansion agents, thereby producing viscoelastic foams that meet or exceed the requirements of BS5852. In some embodiments, the level of toluendiamine present in the viscoelastic foam is less than 5 ppm, based on the total weight of the foam.

Expanding agents suitable for use herein include water, a hydrocarbon, halocarbon.

or volatile halohydrocarbon, or mixtures of two or more such materials, preferably water. Catalysts

Suitable for use herein can be classified as gelation catalysts (eg stannous or tin salts), expansion catalysts (eg amine catalysts), or "balanced" gelation / expansion catalysts. Gelification catalysts promote the reaction between reactive hydrogen atoms, particularly hydroxyl groups, and isocyanates. Expansion catalysts promote the reaction of reactive hydrogen in water and pluriisocyanate. Non-limiting examples of catalysts

Suitable include amine catalysts, tin-based catalysts, bismuth-based catalysts or other organometallic catalysts, and the like. Examples of suitable tertiary amines as an expansion catalyst include, e.g. eg, bis (dimethylaminoethyl) ether and pentamethyldiethylenetriamine. Examples of gelation catalysts include 1,4-diaza (2,2,2) bicyclooctane; tetramethyldipropylenetriamine and tris (dimethylaminopropyl) hydrotriazine.

The following examples will illustrate the present invention, but should not be understood to be limiting in any way.

Examples

In the following examples, the components indicated in the examples were combined to form foams that were subjected to BS 5852 Crib 5 tests, and the results are presented in the examples. The components were combined under standard atmospheric conditions.

In the following examples, the components used were: Polyol OH 56 index: Caradol SC56-02, available from the Shell Chemicals Company; Polyol OH 200 index: Yukol 1030 available from SK Oxichemicals; Amino Catalyst 2: Dabco® 33 LV available from Air Products; Amine catalyst 1: Dabco® A1 available from Air Products or Niax A1 available from GE; Stannous Octoate: Dabco® T9 available from Air Products; and Silicone: GE Niax L 650

or B 8229 from Degussa.

40 EXAMPLE 1: LOW VISCOEL FOAM �? INDEX CONTAINING TCPP / MELAMINE

(COMPARATIVE)

Polyol 1, OH 56 index: 60 parts Polyol 2, OH 300 index: 40 parts Water, php 2.2 Silicone surfactant, php 1 Amine Catalyst 1, php 0.15 Amine Catalyst 2, php 0.2 Stannous Octoate, php 0.28 Antiblaze 81 / TCPP, php 15 Melamine, php 30 �? TDI index 83 Foam density, kg / m3 53 Recovery time, s 6 BS 5852 Crib 5, combustion time, min> 7, se require manual extinction BS5852 Crib 5, weight loss, g> 60, Failure

EXAMPLE 2: VISCOEL FOAM? LOW STICK � INDEX CONTAINING V6 / MELAMINE

(COMPARATIVE)

Polyol 1, OH 56 index: 60 parts Polyol 2, OH 300 index: 40 parts Water, php 2.2 Silicone surfactant, php 1 Amine Catalyst 1, php 0.15 Amine Catalyst 2, php 0.2 Stannous Octoate, php 0.28 Antiblaze V6, php 15 Melamine, php 30 � TDI index 83 Foam density, kg / m3 53 Recovery time, s 6 BS 5852 Crib 5, combustion time, min> 7, extinction required BS5852 Crib 5 manual, weight loss, g> 60, Failure

EXAMPLE 3: VISCOELUM FOAM CONTAINING HIGH DIOL, INDEX, CONTAINING CRX-35 / MELAMINE

Polyol 1, OH 56 index: 60 parts Polyol 2, OH 300 index: 40 parts Water, php 2.2 Silicone surfactant, php 1 Amine Catalyst 1, php. 0.15 Amine Catalyst 2, php 0.2 Stannous Octoate, php 0.28 Protected Diol, OH 56 7.5 Antiblaze RX-35, php 15 Melamine, php 30 Index of TDI 100 Foam Density, kg / m3 55 Recovery Time, s 4.5 BS 5852 Crib 5, burning time, min 5'13 "BS5852 Crib 5, weight loss, g 38, Pass

EXAMPLE 4: VISCOELUM FOAM CONTAINING HIGH DIOL, INDEX, CONTAINING V6 / MELAMINE

Polyol 1, OH 56 index: 60 parts Polyol 2, OH 300 index: 40 parts Water, php 2.2 Silicone surfactant, php 1 Amine Catalyst 1, php 0.15 Amine Catalyst 2, php 0.2 Stannous Octoate, php 0.28 Protected diol, OH 56 7.5 Antiblaze V6, php 15 Melamine, php 30 index of TDI 100 Foam Density, kg / m3 54 Recovery Time, s 5 BS 5852 Crib 5, time of combustion, min 5 '13 "BS5852 Crib 5, weight loss, g 47, Pass

Claims (17)

1. A flexible viscoelastic polyurethane foam formulation comprising: a) flame retardant selected from i) one or more chlorinated phosphate esters, ii) one or more brominated flame retardants, iii) one or more phosphorus-based halogen free flame retardants, or iv) combinations of i), ii) and / or iii ); b) at least one isocyanate having a functionality of at least two; c) at least one diol in which in the range of 50% to 95% of the terminal OH groups of the diol are primary OH groups; and optionally d) one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine; vi) plasticizers, vii) catalysts, viii) water, ix) alternative blowing agents such as methylene chloride, x) pigments, xi) cell openers.

2.

 The formulation according to claim 1, wherein said isocyanates are selected from toluene diisocyanate ("TDI"), diphenylmethane diisocyanate ("MDI") or methylene diisocyanate.

3.

 The formulation according to claim 1, wherein said diols are polyether-or polyester-diols.

Four.

 The formulation according to claim 1, wherein the chlorinated phosphate esters used in the present invention contain in the range of 5 to 15% by weight of organic phosphorus, based on the total weight of the phosphate ester.

5.

 The formulation according to claim 1, wherein the bromine-containing flame retardants contain in the range of 10 to 70% by weight of bromine, based on the total weight of the brominated flame retardant.

6.

 The formulation according to claim 1, wherein the phosphorus-based halogen-free flame retardants contain in the range of 5 to 40% by weight of phosphorus, based on the total weight of the phosphorus-based halogen-free flame retardant.

7.

 The formulation according to claim 1, wherein the flame retardant is a bromine retardant containing bromine.

8.

 The formulation according to claim 1, wherein the flame retardant is a bromine retardant containing bromine selected from bromine containing tetrabromophthalic anhydride diester / ether diol containing bromine.

9.

A method of forming a flexible viscoelastic polyurethane foam comprising contacting in the presence of one or more catalysts:

a) a flame retardant amount of i) one or more chlorinated phosphate esters, ii) one or more brominated flame retardants, iii) one or more phosphorus-based halogen free flame retardants, or iv) combinations of i), ii) and / or iii); b) at least one isocyanate having a functionality of at least two; c) at least one diol in which in the range of 50% to 95% of the terminal OH groups of the diol are primary OH groups; and optionally d) one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine; vi) plasticizers, vii) water, viii) alternative blowing agents such as methylene chloride, ix) pigments, x) cell openers, thereby forming a viscoelastic polyurethane foam.

10.

 The method according to claim 9, wherein said isocyanates are selected from toluene diisocyanate ("TDI"), diphenylmethane diisocyanate ("MDI") or methylene diisocyanate.

eleven.

 The method according to claim 9, wherein said diols are polyether-or polyester-diols.

12.

 The method according to claim 9, wherein the chlorinated phosphate esters used in the present invention contain in the range of 5 to 15% by weight of organic phosphorus, based on the total weight of the phosphate ester.

13.

 The method according to claim 9, wherein the bromine-containing flame retardants contain in the range of 10 to 70% by weight of bromine, based on the total weight of the brominated flame retardant.

14.

 The method according to claim 9, wherein the halogen-free flame retardants based on

Phosphorus contain in the range of 5 to 40% by weight of phosphorus, based on the total weight of phosphorus-based halogen free flame retardant.

fifteen.

 The method according to claim 9, wherein the flame retardant is a bromine retardant containing bromine.

16.

 The method according to claim 9, wherein the flame retardant is a bromine retardant containing bromine selected from tetrabromophthalic anhydride diester / ether diol containing reactive bromine.

17. The flexible viscoelastic polyurethane foam formulation according to claim 1, comprising: a) one or more brominated flame retardants; b) at least one diisocyanate; c) at least one polyoxyalkylene diol in which in the range of 50% to 95% of the terminal OH groups of the diol are 15 primary OH groups; and optionally d) one or more i) surfactants, ii) antioxidants, iii) diluents, iv) chain extenders or crosslinkers, v) synergistic agents, preferably melamine; vi) plasticizers, vii) catalysts, viii) water, ix) alternative blowing agents such as methylene chloride, x) pigments, xi) cell openers. 18. The formulation according to claim 17, wherein the bromine-containing flame retardant is a tetrabromophthalic anhydride diester / ether diol containing reactive bromine.